1,721,018 research outputs found
Advances in MRCP
No full textMagnetic resonance cholangiopancreatography (MRCP) is a medical imaging technique, which uses magnetic resonance to visualize the biliary tree and pancreatic ducts in a non-invasive way. Though several variations of this technique have been developed in the recent years, they all share the use of a heavily T2W pulse sequence, which selectively displays static or slow-moving fluid-filled structures as high intensity areas. The recent development of many three dimensional (3D) sequences has substantially enhanced the quality of the MRCP images. Likewise, the introduction of hepatobiliary contrast media and secretin, has enabled functional assessment of biliary excretion and the exocrine pancreas, respectively.
In this article, we present new MRCP techniques using 3D acquisition and the role of functional MRCP. In addition, we discuss commonly imaged biliary and pancreatic duct pathologies, including congenital anomalies, obstruction, trauma and tumor
Improving Quality and Safety: Efficient Screening for Nephrogenic Systemic Fibrosis in Patient Population Undergoing MRI in a High Volume Radiology Practice
No full textCan Spleen Serve as an Internal Reference on Diffusion-weighted Imaging (DWI) to Enable Characterization of Hepatic Lesions into Benign and Malignant?
No full textCorrelation of Tumor Density Changes on CT with 18FDG PET Activity for Response Assessment in Advance Bile Duct Cancer
No full textTumor Perfusion or Metabolism for Predicting Early and Late Treatment Response in Advanced Rectal Cancer?
No full textPixel distribution analysis: Can it be used to distinguish clear cell carcinomas from angiomyolipomas with minimal fat?
No full textPurpose: To retrospectively determine if pixel histogram analysis of unenhanced computed tomographic (CT) images can be used to distinguish angiomyolipomas (AMLs) with minimal fat from clear cell renal cell carcinomas (CCRCCs). Materials and Methods: The human studies committee approved this HIPAA-complaint study, with waiver of informed consent. Patients with pathologically proved AMLs lacking visible macroscopic fat at CT and patients with pathologically proved CCRCCs were included. Lesions were measured, and a histogram (number of pixels with each attenuation) was calculated electronically within a central region of interest. The percentage of pixels below the attenuation thresholds -20 HU and 10 HU was calculated in both cohorts. The unpaired Student t test was used to compare the average percentage of subthreshold pixels at each threshold. P < .05 indicated a significant difference. The number of lesions with more than the selected percentage of subthreshold pixels was calculated in both groups, and the chi(2) test was used to test the significance of differences between cohorts. The area under the receiver operating characteristic (ROC) curve was used to determine if any percentage of subthreshold pixels could be used to differentiate between the two cohorts. Results: There were 22 patients with pathologically proved AMLs lacking visible macroscopic fat on CT images. Tuberous sclerosis affected three of these patients. Mean maximal transverse lesion diameter was 20 mm (range, 11-38 mm). There were 28 patients in the CCRCC comparison group. Mean maximal transverse lesion diameter was 26 mm (range, 15-36 mm). Neither the Student t test (P < .2 for all thresholds < 0 HU) nor the chi(2) test (P < .15 for all thresholds < 0 HU) revealed a significant difference between cohorts. A lesion with more low-attenuation pixels was significantly more likely to be characterized as CCRCC than as AML with ROC curve analysis. Conclusion: Once AMLs with visible fat on CT images are excluded, pixel histogram analysis cannot be used to distinguish between AMLs and CCRCCs. (C) RSNA, 2008
New and Evolving Concepts in the Imaging and Management of Urolithiasis: Urologists' Perspective
No full textUrolithiasis is a universal problem that has become increasingly prevalent in the United States and has a high rate of recurrence. Imaging of urolithiasis has evolved over the years due to technologic advances and a better understanding of the disease process. Computed tomography (CT) has been the investigation of choice for the evaluation of urinary stone disease. The emergence of multidetector CT and the recent introduction of dual-energy CT have further reinforced the superiority of this modality over other imaging techniques in the management of urolithiasis. Multidetector CT is not limited to simply helping make an accurate diagnosis in patients with stone disease; it is also useful in the assessment of stone burden, composition, and fragility, findings that are helpful in determining appropriate treatment strategies. In addition, multidetector CT is a valuable tool in the follow-up of patients after urologic intervention or institution of medical therapy. Familiarity with recent technologic developments will help radiologists meet the growing expectations of urologists in this setting. In addition, radiologists should be aware of the radiation risks inherent in the imaging of patients with urolithiasis and take appropriate measures to minimize this risk and optimize image quality. (C) RSNA, 2010 .radiographics.rsna.or
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